This invention relates in general to fusing stations used in electrostatographic imaging, and in particular, to fusing stations, which include sleeved rollers. More particularly, the invention relates to externally-heated fuser rollers, useful for color imaging, including removable replaceable sleeve members.
In electrostatographic imaging and recording processes such as electrostatographic reproduction, an electrostatic latent image is formed on a primary image-forming member such as a photoconductive surface and is developed with a thermoplastic toner powder to form a toner image. The toner image is thereafter transferred to a receiver, e.g., a sheet of paper or plastic, and the toner image is subsequently fused to the receiver in a fusing station using heat or pressure, or both heat and pressure. The fuser member can be a roller, belt, or any surface having a suitable shape for fixing thermoplastic toner powder to the receiver. The fusing step in a roller fuser commonly consists of passing the toned receiver between a pair of engaged rollers that produce an area of pressure contact known as a fusing nip. In order to form said nip, at least one of the rollers typically has a compliant or conformable layer on its surface. Heat is transferred from at least one of the rollers to the toner in the fusing nip, causing the toner to partially melt and attach to the receiver. In the case where the fuser member is a heated roller, a resilient compliant layer having a smooth surface is typically used which is bonded either directly or indirectly to the core of the roller. Where the fuser member is in the form of a belt, e.g., a flexible endless belt that passes around the heated roller, it typically has a smooth, hardened outer surface.
Most roller fusers, known as simplex fusers, attach toner to only one side of the receiver at a time. In this type of fuser, the roller that contacts the unfused toner is commonly known as the fuser roller and is usually the heated roller. The roller that contacts the other side of the receiver is known as the pressure roller and is usually unheated. Either or both rollers can have a compliant layer on or near the surface. In most fusing stations comprising a fuser roller and an engaged pressure roller, it is common for only one of the two rollers to be driven rotatably by an external source. The other roller is then driven rotatably by frictional contact.
In a duplex fusing station, which is less common, two toner images are simultaneously attached, one to each side of a receiver passing through a fusing nip. In such a duplex fusing station there is no real distinction between fuser roller and pressure roller, both rollers performing similar functions, i.e., providing heat and pressure.
Two basic types of simplex heated roller fusers have evolved. One uses a conformable or compliant pressure roller to form the fusing nip against a hard fuser roller, such as in a Docutech 135 machine made by the Xerox Corporation. The other uses a compliant fuser roller to form the nip against a hard or relatively non-conformable pressure roller, such as in a Digimaster 9110 machine made by Heidelberg Digital LLC. A fuser roller designated herein as compliant typically comprises a conformable layer having a thickness greater than about 2 mm and in some cases exceeding 25 mm. A fuser roller designated herein as hard comprises a rigid cylinder, which may have a relatively thin polymeric or conformable elastomeric coating, typically less than about 1.25 mm thick. A fuser roller used in conjunction with a hard pressure roller tends to provide easier release of a receiver from the heated fuser roller, because the distorted shape of the compliant surface in the nip tends to bend the receiver towards the relatively non-conformable pressure roller and away from the much more conformable fuser roller.
A conventional toner fuser roller includes a cylindrical core member, often metallic such as aluminum, coated with one or more synthetic layers which typically comprise polymeric materials made from elastomers.
The most common type of fuser roller is internally heated, i.e., a source of heat is provided within the roller for fusing. Such a fuser roller normally has a hollow core, inside of which is located a heating source, usually a lamp. Surrounding the core is an elastomeric layer through which heat is conducted from the core to the surface, and the elastomeric layer typically contains fillers for enhanced thermal conductivity. A different kind of fuser roller which is internally heated near its surface is disclosed by Lee et al. in U.S. Pat. No. 4,791,275, which describes a fuser roller comprising two polyimide Kapton(copyright) sheets (sold by DuPont and Nemours) having a flexible ohmic heating element disposed between the sheets, the polyimide sheets surrounding a conformable polyimide foam layer attached to a core member. According to J. H. DuBois and F. W. John, Eds., in Plastics, 5th Edition, Van Nostrand and Rheinhold, 1974, polyimide at room temperature is fairly stiff with a Young""s modulus of about 3.5 GPa-5.5 GPa (1 GPa=1 GigaPascal=109 Newton/m2), but the Young""s modulus of the polyimide sheets can be expected to be considerably lower at the stated high operational fusing temperature of the roller of at least 450xc2x0 F.
An externally heated fuser roller is used, for example, in an Image Source 120 copier, marketed by Eastman Kodak Company, and is heated by surface contact between the fuser roller and one or more heating rollers. Externally heated fuser rollers are also disclosed by O""Leary, U.S. Pat. No. 5,450,183, and by Derimiggio et al., U.S. Pat. No. 4,984,027.
A compliant fuser roller may comprise a conformable layer of any useful material, such as for example a substantially incompressible elastomer, i.e., having a Poisson""s ratio approaching 0.5. A substantially incompressible conformable layer comprising a poly(dimethyl siloxane) elastomer has been disclosed by Chen et al., in the commonly assigned U.S. patent application Ser. No. 08/879,896, which is hereby incorporated by reference. Alternatively, the conformable layer may comprise a relatively compressible foam having a value of Poisson""s ratio much lower than 0.5. A conformable polyimide foam layer is disclosed by Lee in U.S. Pat. No. 4,791,275, and a lithographic printing blanket is disclosed by Goosen et al. in U.S. Pat. No. 3,983,287, comprising a conformable layer containing a vast number of frangible rigid-walled tiny bubbles which are mechanically ruptured to produce a closed cell foam having a smooth surface.
Receivers remove the majority of heat during fusing. Since receivers may have a narrower length measured parallel to the fuser roller axis than the fuser roller length, heat may be removed differentially, causing areas of higher temperature or lower temperature along the fuser roller surface parallel to the roller axis. Higher or lower temperatures can cause excessive toner offset in roller fusers. However, if differential heat can be transferred axially along the fuser roller by layers within the fuser roller having high thermal conductivity, the effect of differential heating can be reduced.
Improved heat transfer from the core to the surface of an internally heated roller fuser will reduce the temperature of the core as well as that of mounting hardware and bearings that are attached to the core. Similarly, improved heat transfer to the surface of an externally heated fuser roller from external heating rollers will reduce the temperature of the external heating rollers as well as the mounting hardware and bearings attached to the external heating rollers.
When the fuser and pressure rollers of a simplex fusing station are pressed against each other, and the conformable layer is deflected to form the fusing nip, the thickness of the conformable layer is reduced inside the nip. When the conformable layer is substantially incompressible, the average speed of the conformable layer through the fusing nip must be greater than that of other parts of the conformable layer that are well away from the nip, because the volume flow rate of the elastomer is constant around the roller. This results in a surface speed of the conformable roller inside the nip, which is faster than far away from the nip. When, for example, the conformable roller is a driving roller frictionally rotating a relatively non-conformable pressure roller, the pressure roller will rotate faster than if the fuser roller had been non-compliant, a phenomenon known as xe2x80x9coverdrivexe2x80x9d. Overdrive may be expressed quantitatively as a peripheral speed ratio, measured as the ratio of the peripheral surface speeds far away from the nip.
A substantially incompressible elastomer that is displaced in the fusing nip results in an extra thickness of the conformable layer adjacent to either side of the fusing nip, i.e., pre-nip and post-nip bulges. Again, since the elastomer is substantially incompressible, the average speed of the conformable layer in these bulges is less than that of the other parts of the conformable layer that are well away from the nip. The highest pressure in the nip will be obtained at the center of the nip (at the intersection of the joined surfaces and an imaginary line between the centers of the two rollers). Since one roller drives the other, the surface velocities of the rollers should be close to equal at the point of maximum pressure, at the center of the nip. In view of these facts, it may be understood that in general there will be locations in the contact zone of the nip where the surface velocities of the two rollers differ, i.e., there will be slippage. This slippage, which may be substantial just after entry and just before exit of the nip, is a cause of wear which shortens roller life.
A potentially serious problem for fusing arising from the presence of overdrive is xe2x80x9cdifferential overdrivexe2x80x9d, associated for example with tolerance errors in mounting the rollers forming the fusing nip, or with roller runout. Runout can have many causes, e.g., fluctuations in layer thicknesses along the length of a roller, variations in the dimensions of a core member, an acentric roller axis, and so forth. It will be evident that differential overdrive can result in localized differential slippages along the length of a fusing nip, inasmuch as the local effective speed ratio would otherwise tend to fluctuate or change with time along the length of the nip, causing some portions of the driven roller to try to lag and other portions to try to move faster than the average driven speed. Differential overdrive can have serious consequences for fusing, including the formation of large-scale image defects and wrinkling of a receiver.
All rollers suffer from surface wear, especially where the edges of receivers contact the rollers. Since relative motion due to slippage between rollers increases wear, the changes in velocity of the surface of a conformable roller, as it travels into, through, and out of a fusing nip formed with a relatively non-conformable roller, should increase the wear rate of the conformable roller, especially if the conformable roller is the heated fusing member, bearing in mind that a fuser roller typically faces a relatively rough and abrasive paper surface in the nip. Moreover, since the material on the conformable roller is stretched and relaxed each time it passes through the fusing nip, this flexure can result in fatigue aging and wear, including failure of the roller due to splitting or cracking of the compliant material, or even delamination.
To obtain high-quality electrophotographic copier/printer image quality, image defects must be reduced. One type of defect is produced by smearing of image dots or other small-scale image features in the fusing nip. Relative motions associated with overdrive and resulting in localized slippage between rollers in a fusing nip can cause softened toner particles to smear parallel to the direction of motion, resulting for example in elongated dots.
Some roller fusers rely on film splitting of low viscosity oil to enable release of the toner and (hence) receiver from the fuser roller. Relative motion in the fusing nip can disadvantageously disrupt the oil film.
A toner fuser roller commonly includes a hollow cylindrical core, often metallic. A resilient base cushion layer, which may contain filler particles to improve mechanical strength and/or thermal conductivity, is formed on the surface of the core, which may advantageously be coated with a primer to improve adhesion of the resilient layer. Roller cushion layers are commonly made of silicone rubbers or silicone polymers such as, for example, poly(dimethylsiloxane) (PDMS) polymers of low surface energy, which minimize adherence of toner to the roller.
Frequently, release oils composed of, for example, poly(dimethylsiloxanes) are also applied to the fuser roller surface to prevent the toner from adhering to the roller. Such release oils (commonly referred to as fuser oils) may interact with the PDMS in the resilient layer upon repeated use, which in time causes swelling, softening, and degradation of the roller. To prevent these deleterious effects caused by release oil, a thin barrier layer of, for example, a cured polyfluorocarbon, is formed on the cushion layer.
Electrophotography can be used to create high quality multicolor toner images when the toner particles are small, that is, diameters less than about 10 micrometers, and the receivers, typically papers, are smooth. A typical method of making a multicolor toner image involves trichromatic color synthesis by subtractive color formation. In such synthesis, successive imagewise electrostatic images, each representing a different color, are formed on a photoconductive element, and each image is developed with a toner of a different color. Typically, the colors correspond to each of the three subtractive primary colors (cyan, magenta and yellow) and, optionally, black. The imagewise electrostatic images for each of the colors can be made successively on the photoconductive element by using filters to produce color separations corresponding to the colors in the image. Following development of the color separations, each developed separation image can be transferred from the photoconductive element successively in registration with the other color toner images to an intermediate transfer member. All the color toner images can then be transferred in one step from the intermediate transfer member to a receiver, where they are fixed or fused to produce a multicolor permanent image. Alternatively, an electrophotographic apparatus comprising a series of tandem modules may be employed, such as disclosed by Herrick et al. in U.S. Pat. No. 6,016,415, wherein color separation images are formed in each of four color modules and transferred in register to a receiver member as the receiver member is moved through the apparatus while supported on a transport web.
To rival the photographic quality produced using silver halide technology, it is desirable that these multicolor toner images have high gloss. To this end, it is desirable to provide a very smooth fusing member contacting the toner particles in the fusing station.
In the fusing of the toner image to the receiver, the area of contact of a conformable fuser roller with the toner-bearing surface of a receiver sheet as it passes through the fusing nip is determined by the amount pressure exerted by the pressure roller and by the characteristics of the resilient cushion layer. The extent of the contact area helps establish the length of time that any given portion of the toner image will be in contact with and heated by the fuser roller.
A fuser module is disclosed by M. E. Beard et al., in U.S. Pat. No. 6,016,409, which includes an electronically-readable memory permanently associated with the module, whereby the control system of the printing apparatus reads out codes from the electronically readable memory at install to obtain parameters for operating the module, such as maximum web use, voltage and temperature requirements, and thermistor calibration parameters.
As previously mentioned, PDMS cushion layers may include fillers comprising inorganic particulate materials, for example, metals, metal oxides, metal hydroxides, metal salts, and mixtures thereof. For example, U.S. Pat. No. 5,292,606, the disclosure of which is incorporated herein by reference, describes fuser roller base cushion layers that contain fillers comprising particulate zinc oxide and zinc oxide-aluminum oxide mixtures. Similarly, U.S. Pat. No. 5,336,539, the disclosure of which is incorporated herein by reference, describes a fuser roller cushion layer containing dispersed nickel oxide particles. Also, the fuser roller described in U.S. Pat. No. 5,480,724, the disclosure of which is incorporated herein by reference, includes a base cushion layer containing 20 to 40 volume percent of dispersed tin oxide particles.
Filler particles may also be included in a barrier layer. For example, in Chen et al., U.S. Pat. No. 5,464,698, the disclosure of which is incorporated herein by reference, is described a toner fuser member having a silicone rubber cushion layer and an overlying layer of a cured fluorocarbon polymer in which is dispersed a filler comprising a particulate mixture that includes tin oxide.
Chen et al., in commonly assigned U.S. patent application Ser. No. 08/879,896, disclose an improved fuser roller including three concentric layers each comprising a particulate filler, i.e., a base cushion layer comprising a condensation-cured PDMS, a barrier layer covering the base cushion and comprised of a cured fluorocarbon polymer, and an outer surface layer comprising an addition-cured PDMS, the particulate fillers in each layer including one or more of aluminum oxide, iron oxide, calcium oxide, magnesium oxide, tin oxide, and zinc oxide. The barrier layer, which may comprise a Viton(trademark) elastomer (sold by DuPont) or a Fluorel(trademark) elastomer (sold by Minnesota Mining and Manufacturing), is a relatively low modulus material typically having a Young""s modulus less than about 10 MPa, and it therefore has a negligible effect upon the mechanical characteristics of the roller, including overdrive.
Vrotacoe et al., in U.S. Pat. No. 5,553,541, disclose a printing blanket, for use in an offset printing press, which includes a seamless tubular elastic layer comprising compressible microspheres, surrounded by a seamless tubular layer made of a circumferentially inextensible material, and a seamless tubular printing layer over the inextensible layer. It is disclosed that provision of the inextensible layer reduces or eliminates pre-nip and post-nip bulging of the roller when printing an ink image on a receiver sheet, thereby improving image quality by reducing or eliminating ink smearing caused by slippage associated with the formation of bulges in the prior art.
Fusing stations can include flexible, high-modulus stiffening layers with internally-heated and externally-heated compliant toner fuser rollers, as well as in compliant pressure rollers. Excessive fuser roller wear and toner image dot smearing are commonly caused by overdrive in the fusing nip, as typically found in prior art rollers. The stiffening layer reduces wear and improves image quality by greatly reducing overdrive, or making it negligible.
The use of a removable endless belt or tubular type of blanket on an intermediate roller has long been practiced in the offset lithographic printing industry, as recently disclosed by Gelinas in U.S. Pat. No. 5,894,796 wherein the tubular blanket may be made of materials including rubbers and plastics and may be reinforced by an inner layer of aluminum or other metal. As disclosed earlier, for example, by Julian in U.S. Pat. No. 4,144,812, an intermediate lithographic roller comprises a portion having a slightly smaller diameter than the main body of the roller, such that a blanket member may be slid along this narrower portion until it reaches a location where a set of holes located in the roller allow a fluid under pressure, e.g., compressed air, to pass through the holes, thereby stretching the blanket member and allowing the entire blanket member to be slid onto the main body of the roller. After the blanket is located in a suitable position, the source of compressed air or fluid under pressure is turned off, thereby allowing the blanket member to relax to a condition of smaller strain, such strain being sufficient to cause the blanket member to snugly embrace the roller.
An intermediate transfer roller consisting of a rigid core and a removable, replaceable intermediate transfer blanket has been disclosed by Landa et al., in U.S. Pat. No. 5,335,054, and by Gazit et al., in U.S. Pat. No. 5,745,829, whereby the intermediate transfer blanket is fixedly and replaceably secured and attached to the core. The intermediate transfer blanket, disclosed for use in conjunction with a liquid developer for toning a primary image, consists of a substantially rectangular sheet mechanically held to the core by grippers. The core (or drum) has recesses where the grippers are located. It will be evident from U.S. Patent Nos. 5,335,054 and 5,745,829 that, owing to the presence of the recesses, the entire surface of the intermediate transfer drum cannot be utilized for transfer, which is a disadvantage requiring costly means to maintain a proper orientation of the useful part of the drum when transferring a toner image from a primary imaging member to the intermediate transfer roller, or, when transferring a toner image from the intermediate transfer roller to a receiver. Moreover, the fact that the blanket does not form a continuous covering of the entire core surface, owing to the fact that two of its edges are held by grippers, is similarly a disadvantage. Another disadvantage arises because there is inevitably a gap between these edges, so that contamination can become deposited there which may lead to transfer artifacts.
Commonly assigned copending U.S. patent application Ser. No. 09/457,455, by T. N. Tombs et al., hereby incorporated by reference, discloses a single-sleeved intermediate transfer roller and method of using in an electrostatographic color reproduction machine. The intermediate transfer roller comprises a central member plus a replaceable removable sleeve member. This improves over U.S. Pat. Nos. 5,335,054 and 5,745,829 in that the sleeve member is in the form of an endless belt. The central member remains attached to a frame portion of the machine when the sleeve member is removed and replaced. A sleeve member comprises one or more compliant layers and may also include a stiffening layer. In some embodiments a central member may comprise a core member and a thick compliant layer coated on the core member.
An electrostatographic imaging member in the form of a removable replaceable endless imaging belt on a rigid roller is disclosed by Yu et al., in U.S. Pat. No. 5,415,961. The electrostatographic imaging member is placed on the rigid roller and removed from the rigid roller by means involving stretching the endless imaging belt with a pressurized fluid.
Mammino et al., in U.S. Pat. Nos. 5,298,956 and 5,409,557, disclose a reinforced seamless intermediate transfer member that may be in the shape of a belt, sleeve, tube or roll and comprising a reinforcing member in an endless configuration having filler material and electrical property regulating material on, around or embedded in the reinforcing member. The reinforcing member may be made of metal, synthetic material or fibrous material, and has a tensile modulus ranging from about 400,000 to more than 1,000,000 psi (2.8 to more than 6.9 GPa). The intermediate transfer member has a thickness between 2 mils and about 7 mils.
May and Tombs in U.S. Pat. Nos. 5,715,505 and 5,828,931 disclose a primary image forming member roller comprising a thick compliant blanket layer coated on a core member, the thick compliant blanket surrounded by a relatively thin concentric layer of a photoconductive material. The compliant primary imaging roller provides improved electrostatic transfer of a toner image directly to a receiver member. It is disclosed that the compliant imaging roller can be used bifunctionally, i.e., it may serve also as an intermediate member for electrostatic transfer of a toner image to a receiver. U.S. Pat. No. 5,732,311 discloses a compliant electrographic primary imaging roller. Disclosures in U.S. Pat. Nos. 5,715,505, 5,828,931 and 5,732,311 are hereby incorporated by reference.
Commonly assigned copending U.S. patent application Ser. No. 09/680,133, by M. F. Molaire et al., discloses a single-sleeved compliant primary imaging roller and a method of making. The sleeve is a photoconductive member, the sleeve resting on a compliant layer formed on a core member. This improves over U.S. Pat. Nos. 5,715,505 and 5,828,931, in that the layers comprising the roller are made more reliably and more cheaply, and also that the photoconductive sleeve may be readily removed and replaced when at the end of its useful life, thereby lowering cost and reducing downtime. Commonly assigned copending U.S. patent application Ser. No. 09/680,133, by M. F. Molaire, et al., hereby incorporated by reference, also improves over U.S. Pat. No. 5,415,961 by providing a core member having a thick compliant layer over which the sleeve member is placeable and removable.
A sleeved intermediate transfer member having a central member comprising a thick compliant layer coated on a rigid core member, as disclosed in commonly assigned copending U.S. patent application Ser. No. 09/475,455 by T. N. Tombs, et al., is disadvantageously subject to damage of the compliant layer when removing or replacing a sleeve member. A compliant layer on a rigid core of a sleeved PIFM, as disclosed in commonly assigned copending U.S. Patent application Ser. No. 09/680,133 by M. F. Molaire, et al., may also be subject to damage when removing or replacing a photoconductive sleeve member.
Double-sleeved intermediate transfer rollers and primary image-forming rollers are disclosed in commonly assigned copending U.S. patent application Ser. No. 09/679,016 by J. W. May, et al., hereby incorporated by reference. An inner sleeve provides macro-compliance, i.e., the ability to conform to form a nip. An outer sleeve provides micro-compliance, which comes into play at, for example, the scale of individual toner particles, paper roughness, and edges of large toned solid areas. In commonly assigned copending U.S. patent application Ser. No. 09/679,016 by J. W. May, et al., a double-sleeved intermediate transfer or primary image-forming roller comprises a costly, highly toleranced, rigid, core member, and the ability to replace the sleeves preserves the core member for multiple reuses, thereby cutting overall costs. Moreover, it is disclosed that a stiffening layer can be included as an exterior outer surface of an inner sleeve or as an exterior inner surface of an outer sleeve. Additionally, either sleeve may be replaced without replacing the other, or else the inner and outer sleeves may be replaced with differing frequencies.
There remains a need to provide improved externally-heated fuser rollers and pressure rollers that lower overall costs when employed in a fusing station, while otherwise maintaining the advantages of fusing station rollers which include a stiffening layer. Typical fuser rollers and pressure rollers, which are subject to aging, damage, and wear, are bulky, heavy, and expensive to store and to ship. Sleeved rollers of the present invention have relatively lightweight, easily replaceable, surface layers, and therefore they satisfy the need to drive down overall operational costs by avoiding the necessity of manufacturing and shipping complete rollers when replacements in a fusing station are required.
The invention provides an improved fusing station of an electrostatographic machine. The fusing station includes a conformable or compliant multilayer roller, which has a rigid core member and a removable replaceable compliant sleeve member. The multilayer roller can be an externally heated fuser roller, or a pressure roller. The sleeve member of the multilayer roller is removable from the core member when the sleeve member needs replacing due to wear or damage, or when the sleeve member is at the end of a predetermined operational life. A new sleeve member may then be installed, e.g., on an expensive, finely toleranced core member, thereby providing a large cost saving by retaining the expensive core member for a long operational usage. Another advantage of the sleeve member of the inventive multilayer roller is being able to ship lighter and less bulky sleeve parts, as compared to shipping entire replacement rollers of prior art fusing stations. Moreover, the core member may preferably remain fixed to the electrostatographic apparatus in which it is mounted during removal or replacement of a sleeve member. The sleeve member includes one or more elastomeric layers and also preferably a flexible high-modulus stiffening layer. In different embodiments, a fusing station of the invention may include an externally heated sleeved compliant fuser roller and a sleeved compliant pressure roller, or it may include an externally heated sleeved compliant fuser roller and a hard pressure roller. In another embodiment, an externally heated hard fuser roller may be used with a sleeved compliant pressure roller. A multilayer sleeved inventive roller may be used in simplex and duplex fusing stations. In a duplex station, each of the rollers providing the fusing nip is provided with an external source of heat and preferably has a compliant sleeve.
In accordance with the invention, there is provided a conformable roller for use in a fusing station of an electrostatographic machine, the fusing station being provided with a pressure roller and a fuser roller for fusing a toner image on a receiver, the fuser roller made from a plurality of layers surrounding an axis of rotation, the conformable roller including: a rigid cylindrically symmetric core member; a flexible replaceable removable compliant sleeve member in the form of a tubular belt surrounding and nonadhesively intimately contacting the core member; and, the fusing station including an external heat source for the fuser roller, at least one of the plurality of layers being thermally resistive.
In accordance with another aspect of the invention there is provided a sleeve member, included in a conformable roller of a fusing station of an electrostatographic machine, the fusing station being provided with a pressure roller and a fuser roller for fusing a toner image on a receiver, the fuser roller being provided with an external heat source, the conformable roller including both a core member and a sleeve member, the sleeve member including: a tubular strengthening band; a compliant base cushion layer formed on the strengthening band; an optional barrier layer coated on the base cushion layer; an outer layer coated on the barrier layer; and, wherein the sleeve member has the form of a tubular belt surrounding and nonadhesively intimately contacting the core member.
In accordance with yet another aspect of the invention there is provided a sleeve member, included in a conformable roller of a fusing station of an electrostatographic machine, the fusing station being provided with a pressure roller and a fuser roller for fusing a toner image on a receiver, the fuser roller being provided with an external heat source, the conformable roller including both a core member and a sleeve member, the sleeve member including: a tubular strengthening band; a compliant base cushion layer formed on the strengthening band; a stiffening layer in intimate contact with and surrounding the base cushion layer; an outer layer on the stiffening layer; and, wherein the sleeve member has the form of a tubular belt surrounding and nonadhesively intimately contacting the core member.
In accordance with an additional aspect of the invention there is provided an inner sleeve member, included in a conformable roller of a fusing station of an electrostatographic machine, the fusing station being provided with a pressure roller and a fuser roller for fusing a toner image on a receiver, the fuser roller being provided with an external heat source, the conformable roller including both a core member and an inner sleeve member and an outer sleeve member, the inner sleeve member including: a tubular strengthening band; a compliant base cushion layer formed on the strengthening band; a protective layer on the base cushion layer; and, wherein the inner sleeve member has the form of a tubular belt surrounding and nonadhesively intimately contacting the core member.
In accordance with a further additional aspect of the invention there is provided an outer sleeve member, included in a conformable roller of a fusing station of an electrostatographic machine, the fusing station being provided with a pressure roller and a fuser roller for fusing a toner image on a receiver, the fuser roller being provided with an external heat source, the conformable roller including both a core member and an inner sleeve member and an outer sleeve member, the outer sleeve member including: a tubular stiffening layer; an outer layer on the stiffening layer; and, wherein the outer sleeve member has the form of a tubular belt surrounding and nonadhesively intimately contacting the inner sleeve member.
In accordance with a still yet another aspect of the invention, there is provided a fusing station of an electrostatographic machine which includes: a rotating externally heated compliant fuser roller and a counter-rotating hard pressure roller engaged to form a fusing nip with the compliant fuser roller, the compliant fuser roller including a flexible replaceable removable compliant sleeve member in the form of a tubular belt surrounding and nonadhesively intimately contacting a rigid cylindrical core member, the sleeve member including a tubular strengthening band, a base cushion layer formed on the strengthening band, a stiffening layer in intimate contact with the base cushion layer such that the stiffening layer has a Young""s modulus in a range of approximately 0.1 GPa to 500 GPa and a thickness less than about 500 micrometers, and an outer layer on the stiffening layer.
In accordance with a further aspect of the invention, there is provided a fusing station of an electrostatographic machine which includes: a rotating externally heated compliant fuser roller including a flexible replaceable removable compliant sleeve member in the form of a tubular belt surrounding and nonadhesively intimately contacting a rigid cylindrical core member, the sleeve member including a tubular strengthening band, a base cushion layer formed on the strengthening band, a stiffening layer in intimate contact with the base cushion layer such that the stiffening layer has a Young""s modulus in a range of approximately 0.1 GPa to 500 GPa and a thickness less than about 500 micrometers, and an outer layer on the stiffening layer; and, a counter-rotating compliant pressure roller engaged to form a fusing nip with the compliant fuser roller, the pressure roller including a flexible replaceable removable compliant sleeve member in the form of a tubular belt surrounding and nonadhesively intimately contacting a rigid cylindrical core member, the sleeve member including a tubular strengthening band, a base cushion layer formed on the strengthening band, a stiffening layer in intimate contact with the base cushion layer such that the stiffening layer has a Young""s modulus in a range of approximately 0.1 GPa to 500 GPa and a thickness less than about 500 micrometers, and an optional outer layer on the stiffening layer.
In accordance with yet a further aspect of the invention, there is provided a fusing station of an electrostatographic machine which includes: a rotating compliant pressure roller and a counter-rotating externally heated hard fuser roller engaged to form a fusing nip with the compliant pressure roller, the compliant pressure roller including a flexible replaceable removable compliant sleeve member in the form of a tubular belt surrounding and nonadhesively intimately contacting a rigid cylindrical core member, the sleeve member including a tubular strengthening band, a base cushion layer formed on the strengthening band, a stiffening layer in intimate contact with the base cushion layer such that the stiffening layer has a Young""s modulus in a range of approximately 0.1 GPa to 500 GPa and a thickness less than about 500 micrometers, and an outer layer on the stiffening layer.
In accordance with a still yet further aspect of the invention, there is provided a fusing station of an electrostatographic machine which includes: a rotating first heated fuser roller; a counter-rotating second heated fuser roller engaged to form a pressure fusing nip with the first fuser roller; wherein at least one of the first and second heated fuser rollers further includes a flexible replaceable removable compliant sleeve member in the form of a tubular belt surrounding and nonadhesively intimately contacting a rigid cylindrical core member, the sleeve member including a tubular strengthening band, a base cushion layer formed on the strengthening band, a stiffening layer in intimate contact with the base cushion layer such that the stiffening layer has a Young""s modulus in a range of approximately 0.1 GPa to 500 GPa and a thickness less than about 500 micrometers, and an outer layer on the stiffening layer; and, wherein at least one of the first and second heated fuser rollers is heated by an external source of heat.
In accordance with an additional aspect of the invention, there is provided a toner fusing method, for use in an electrostatographic machine having a fusing station according to claim 14, the toner fusing method comprising the steps of: forming a fusing nip by engaging the rotating compliant fuser roller having an external source of heat and the counter-rotating hard pressure roller, one of the rollers being a driven roller and the other frictionally driven by pressure contact in the nip; forming an unfused toner image on a surface of a receiver sheet; feeding the leading edge of the receiver into the nip and allowing the unfused toner image on the receiver sheet to pass through the fusing nip with the unfused toner image facing the fuser roller; wherein the compliancy in combination with the stiffening layer included in the fuser roller provide a reduced wear rate of the fuser roller and an improved quality of a toner image fused by the fusing station.
In accordance with another additional aspect of the invention, there is provided a toner fusing method, for use in an electrostatographic machine having a fusing station according to claim 17, said toner fusing method comprising the steps of: forming a fusing nip by engaging the rotating compliant fuser roller having an external source of heat and the counter-rotating hard pressure roller, one of the rollers being a driven roller and the other frictionally driven by pressure contact in the nip; forming an unfused toner image on a surface of a receiver sheet; feeding the leading edge of the receiver into the nip and allowing the unfused toner image on the receiver sheet to pass through the fusing nip with the unfused toner image facing the fuser roller; and, wherein a low cost of ownership of the fusing station is provided by use of the replaceable removable sleeve member.
In accordance with yet another additional aspect of the invention, there is provided a method of making a sleeve member of claim 9 including the steps of: providing a cylindrical mandrill; mounting on the mandrill the strengthening band by sliding the strengthening band over the mandrel to a suitable position, the sliding being accomplished by making an inner diameter of the strengthening band temporarily larger during the sliding than an outer diameter of the mandrel; forming the base cushion layer on the strengthening band; uniformly coating the base cushion layer by the barrier layer; uniformly coating the barrier layer by the outer layer to form a completed sleeve member; and, sliding the completed sleeve member off the mandrill, the sliding being accomplished by making an inner diameter of the sleeve member temporarily larger during the sliding than an outer diameter of the mandrill.
In accordance with still another additional aspect of the invention, there is provided a method of making a sleeve member of claim 10 including the steps of: providing a cylindrical mandrill; mounting on the mandrill the strengthening band by sliding the strengthening band over the mandrel to a suitable position, the sliding being accomplished by making an inner diameter of the strengthening band temporarily larger during the sliding than an outer diameter of the mandrel; forming the base cushion layer on the strengthening band; providing the stiffening layer in the shape of a seamless metal tube; sliding the metal tube over an outer surface of the base cushion layer, the metal tube having, prior to the sliding of the metal tube, an inner diameter smaller than an outside diameter of the base cushion layer formed on the strengthening band, the sliding being accomplished by making the inner diameter of the metal tube temporarily larger during the sliding than the outside diameter of the base cushion layer; uniformly coating the metal tube by the outer layer to form a completed sleeve member; sliding the completed sleeve member off the mandrill, the sliding being accomplished by making an inner diameter of the sleeve member temporarily larger during the sliding than an outer diameter of the mandrill.
In accordance with still yet another additional aspect of the invention, there is provided a method of making an inner sleeve member of claim 11, including the steps of: providing a cylindrical mandrill; mounting on the mandrill a strengthening band by sliding the strengthening band over the mandrel to a suitable position, the sliding being accomplished by making an inner diameter of the strengthening band temporarily larger during the sliding than an outer diameter of the mandrel; forming a base cushion layer on the strengthening band; optionally coating the base cushion layer with a protective layer to form a completed inner sleeve member; and, sliding the completed inner sleeve member off the mandrill, the sliding being accomplished by making an inner diameter of the inner sleeve member temporarily larger during the sliding than an outer diameter of the mandrill.
In accordance with a still yet further additional aspect of the invention, there is provided a method of making an outer sleeve member of claim 12, including the steps of: providing a cylindrical mandrill; mounting on the mandrill a stiffening layer by sliding the stiffening layer over the mandrel to a suitable position, the sliding being accomplished by making an inner diameter of the stiffening layer temporarily larger during the sliding than an outer diameter of the mandrel; coating the stiffening layer by an outer layer to form a completed outer sleeve member; and, sliding the completed outer sleeve member off the mandrill, the sliding being accomplished by making an inner diameter of the outer sleeve member temporarily larger during the sliding than an outer diameter of the mandrill.